Perimeter = \(2 \times (\text{length} + \text{width}) = 2 \times (8 + 5) = 26 \, \text{cm}\).

["# Understanding Perimeter: How to Calculate the Boundary of a Rectangle (with Example = 26 cm)", "The perimeter is a fundamental concept in geometry, essential for anyone studying math, architecture, interior design, or construction. But what exactly is perimeter? In simple terms, perimeter is the total length around the outer edge of a shape. When dealing with a rectangle — one of the most common shapes in both nature and design — calculating perimeter is straightforward.", "## What Is the Perimeter of a Rectangle?", "For a rectangle, the perimeter formula is:", "[\n\ ext{Perimeter} = 2 \ imes (\ ext{length} + \ ext{width})\n]", "This formula works because a rectangle has two pairs of equal sides: the length (the longer side) and the width (the shorter side). Since each length runs parallel to its opposite, and the same applies to the widths, adding them together and doubling accounts for the full boundary.", "### Example: Perimeter = 26 cm", "Let’s say we have a rectangle with:", "- Length = 8 cm\n- Width = 5 cm", "Plug these values into the perimeter formula:", "[\n\ ext{Perimeter} = 2 \ imes (8 , \ ext{cm} + 5 , \ ext{cm}) = 2 \ imes 13 , \ ext{cm} = 26 , \ ext{cm}\n]", "Thus, the perimeter of this rectangle is 26 cm — the total distance around its boundary. This value is crucial for practical applications, such as determining how much fencing is needed, wallpaper required, or border length for design projects.", "## Why Is Perimeter Important?", "- Construction & DIY: Accurate perimeter measurements ensure materials are ordered correctly.\n- Landscaping: Calculating yard or garden boundaries helps plan edging and planting areas.\n- Math Education: Perimeter is a foundational concept that teaches spatial reasoning and algebraic relationships.", "## Final Thoughts", "Understanding and calculating perimeter is simple with the formula (2 \ imes (\ ext{length} + \ ext{width})), and it becomes quick with practice. Whether you’re solving a textbook problem or planning real-world projects, knowing that a rectangle with length 8 cm and width 5 cm has a perimeter of 26 cm empowers practical problem-solving.", "If you want to explore perimeter in different shapes or dive deeper into geometry, stay tuned to our ongoing series — all aimed at making math intuitive and applicable!", "---", "Keywords: perimeter formula, rectangle perimeter, perimeter calculation 2 × (length + width), perimeter example 8 × 5, geometry basics, practical perimeter applications, how to calculate perimeter cm", "Meta Description: Learn how to calculate perimeter of a rectangle using the formula (2 \ imes (\ ext{length} + \ ext{width})). Example: length 8 cm and width 5 cm gives a perimeter of 26 cm — perfect for DIY, construction, and math lessons."]